Solvent-Impregnated Sorbents for Tantalum from Niobium Separation Using a Fixed-Bed Column.

Magdalena Turkowska,Andrzej Milewski,Krzysztof Karoń,Agata Jakóbik-Kolon

doi:10.3390/ma15041513

Magdalena Turkowska, Andrzej Milewski + Show 2 more

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https://doi.org/10.3390/ma15041513

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Abstract

Reactor-grade niobium steel is used as a construction material for nuclear reactors. In this case, the presence of tantalum, which is characterized by a 20 times higher active cross section for capturing thermal neutrons than the cross section of niobium (181Ta: 21.3 barn), cannot exceed 100 ppm. Analytical methods for quality and new separation method development control need very pure niobium matrices—niobium compounds with a low tantalum content, which are crucial for preparing matrix reference solutions or certified reference materials (CRMs). Therefore, in this paper, a new, efficient method for separating trace amounts of Ta(V) from Nb(V) using extraction chromatography with the use of sorbents impregnated with methyl isobutyl ketone MIBK solvent is proposed. Various types of MIBK-impregnated sorbents were used (AG® 1-X8 Anion Exchange Resin, AMBERLITE™ IRC120 Na Ion Exchange Resin, SERVACEL® Cellulose Anion Exchangers DEAE 52, active carbons of various grain size, carbonized blackcurrant pomace, carbonized chokeberry pomace, bentonite, and polyurethane foam in lumps). The highest tantalum removal efficiency was determined using active coal-based materials (>97%). The separation effectivity of tantalum from niobium was also determined in dynamic studies using a fixed-bed column with MIBK-impregnated active carbon. Solutions of various Nb:Ta weight ratios (1:1, 100:1, 1000:1) were used. The most impressive result was obtaining 70 mL of high purity niobium solution of tantalum content 0.027 ppm (in relation to Nb) with 88.4% yield of niobium from a solution of Nb:Ta, weight ratio 1000:1 (purge factor equaled 35,000). It proves the presented system to be applicable for preparation of pure niobium compounds with very low contents of tantalum.

Highlights

Niobium (Nb) and tantalum (Ta) are extremely important for a number of industrial branches, including the automotive, aviation, and space, construction, military, nuclear, electronic, and chemical industries [1,2] as well as for implantology [3]
These studies are intended to show the possibility of obtaining very pure niobium matrices, namely niobium compounds with a low Ta content, which are crucial for preparing matrix reference solutions or certified reference materials (CRMs)
On the basis of results presented in this paper, we propose a new, efficient method for separating trace amounts of Ta(V) from Nb(V) using extraction chromatography with the use of active carbon impregnated with methyl isobutyl ketone C6 H12 O (MIBK) solvent

Summary

Introduction

Niobium (Nb) and tantalum (Ta) are extremely important for a number of industrial branches, including the automotive, aviation, and space, construction, military, nuclear, electronic, and chemical industries [1,2] as well as for implantology [3]. The major application of tantalum is the production of electronic capacitors (60% of annual production of tantalum is used for the production of powder for capacitors) and specialized alloys for cutting tools, implants, military ammunition, and plane parts. Despite their strategic applications, Nb and Ta remain sparsely known elements to the majority of the public, and relatively little attention is paid to processing these two elements [11]

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